radiator vapor lock?

chilly

Is it possible for a radiator to vapor lock? I have 2 radiators on the end of the main line. one on the first floor, the other upstairs. When the heat comes on, the radiators start out playing nice with air coming out the vents and then about 15 - 20 minutes in, the air stops. All other radiators are hissing madly away and these two stay cold. I insulated the pipes and checked the pitch and all seems ok.

Any ideas out there oh steam guru's?

It's a 1 pipe steam system.

chilly

radiator vapor lock?

just wanted to add that after the first push of steam I get water hammer on these radiators and then the second cycle of boiler action, the radiators start to heat up.

what the heck is going on?

I called someone and they told me I must not be waiting long enough. I should turn the thermostat up higher etc.

Steamhead

Check your main vents

I'll bet they're either too small, or missing completely.

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chilly

I checked and do have vents on the main line. The one on the side with the slow to heat radiators did have some water spitting out. Should I get somebody to replace this one?

chilly

main vents

Steamhead, I wish I could fly you up to MA to fix my system. You'd probably have it diagnosed in 5 minutes. I checked the main vent on the troublesome side and I think it was clogged or broken. I'm going to buy a new main vent and see about getting it replaced.

thanks for the help

I got "the lost art of steam heating" today I'm going to try and convince my boiler guy to read it.

Steamhead

Before you buy a vent

measure the length and diameter of each of your steam mains. With this info we can tell you what you need.

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Mark Eatherton1

Fly by wire...

save yourself a few thousand dollars and take some digital pictures of your near boiler piping.Don't make them too close, but then again don't take the pictures too far away either. Multiple shots are free. Just don't make them the same view. Send us some pictures of the offending radiacalorifiers (heat emmitters)too...

I've seen Frank work his magic here before. Prepare yourself for a learnin' experience from THE best steam person I know. Heck, who knows, this could end up on a segment of This Old House, or Earth Friendly Home and Garbage or something... Richard, you watching this?:-)

I know I'm going to learn something. I've personally trouble shot the system in my own mind, but I want to see what Mr Steamhead does...:-)

Good Luck Frank!


Ahh... The POWER of the internet...Ain't it amazing!


ME

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chilly

main vent pictures

First of all the main comes up from the boiler and T's. The one side is about 5 feet long. The other is about 12 or 13 feet. That is the side with the "vapor lock".

The pictures I got are of the 2 "main" vents. They are on the returns, not on the main as best as I can tell.

The vent on the "short side of the main" is on a nipple about 8 inches long. The vent on the "long side of the main" is on a nipple about 3 - 4 inches long and it's got rust and stuff that has dripped down the side.

I'm also including a picture of my vintage pressuretrol. It doesn't have one of those funny loops. And when I opened it up it was set a 2 and a differential of 3.

I had to crop the pictures down from their original size, but if you need more to help me out let me know.

thanks again to Steamhead and Mark

chilly

main vent diameter

sorry missed this, the main's are 3 inch in diameter, but the vents are on the 1 1/2 inch returns

Steamhead

On those short 3-inch mains

Vent the short main with a Hoffman #4A, and the longer one with a Gorton #1 or Hoffman #75. Reset your pressuretrol to cut out at 1-1/2 pounds and cut in at 1/2 pound. The steam will now reach the ends of both mains quickly and simultaneously.

I'm not sure, but those old Detroit pressuretrols may have had built-in syphons. As long as it works properly I'd leave the piping as is.

Mark, thanks for the kind words!

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chilly

steamhead, more pictures

I've included the main riser? The branches off to the mains, and then the loop from the main to the returns I think.

This set up has been in the house since I moved in 15 years ago. And after some renovations this year. (1 radiator added) I'm having some problems with the 2 radiators on the other end of the main.

chilly

Steamhead

sorry, as I was posting the pictures, you were replying.

I'll give it a try. Thanks

and have a happy Thanksgiving.